Snoop Dogg had an unusual request on his Sundance Film Festival rider. Sources tell us the rapper insisted that watermelon-flavored bubble gum be stocked backstage for his performance at Express Rocks at Harry O’s on Thursday. Organizers had already filled the pot-smoking star’s dressing room with snacks before someone realized the gum was missing. “So staffers combed all of Park City for watermelon-flavored gum,” said an insider. It took rounds of phone calls to stores all over town before someone tracked down the gum at one market. Despite all that effort, Snoop didn’t have much time for snacks — he arrived at the venue right before he took the stage at midnight, after Lil’ Jon had spun records for about an hour. Lil’ Jon hyped up the audience by shouting, “We are in Park City and the altitude ain’t the only thang that’s high tonight.”